Editing Precursor

{{Status|Canon}}
{{Species infobox
|name=Precursors
|othernames=
|image=[[File:Enc22 Primordial.png|300px]]<br>The Primordial, a member of the Precursors
|homeworld=Extragalactic
|height=
|weight=
|distinctions=Tentacle draped mouths, gigantic stature, able to change physical forms at will.
|lifespan=
|techlevel=[[Technological_Achievement_Tiers#Tier_0:_Transsentient|Tier 0]]<ref name="BES">'''[[Bestiarum]]''', page 26: '''''Tier 0: Transsentient''' As the [Forerunners] had no examples of civilizations with technological accomplishment greater than themselves - with the exception of the Precursors - this is a theoretical ceiling. They can travel intergalactic and accelerate evolution of intelligent life. These may be creatures of legend.''</ref>
|notable-group= 
|notable-person=[[Primordial]]
}}
{{Quote|We are the last of those who gave you breath and form, millions of years ago. We are the last of those your kind defied and ruthlessly destroyed. We are the last Precursors. And now we are ''legion''.|The [[Gravemind]] to [[Catalog]] in the final years of the [[Forerunner-Flood war]]<ref>'''Halo: Silentium''', ''page 175''</ref>}}

The '''Precursors''' were an advanced race that preceded and were mythologized by the [[Forerunner]]s. The Forerunners classified them as "[[Technological Achievement Tiers#Tier 0: Transsentient|Transsentient]]" beings, having the ability to travel among galaxies and accelerate the evolution of intelligent life.{{Ref/Reuse|BES}} While the Precursors themselves had long since disappeared during the time of the Forerunners, evidence of their technological and architectural achievements remained scattered across not only the galaxy but also outside it, namely in the [[Large Magellanic Cloud]].

==Forerunner beliefs==
The Forerunners knew few concrete details about the Precursors, and most of their supposed knowledge came from the mythology they had constructed around their creators. Their most central belief was that the [[Mantle]] (the role of guardianship of the galaxy and of all life) was bestowed upon them by the Precursors. From a Forerunner perspective, the passing of the Mantle secured the Precursors' legacy in the form of the Forerunners, continuing their work after they departed, much in the same way [[Human|humanity]] was appointed to be the Forerunners' inheritors shortly before the activation of the [[Halo Array]]. According to Forerunner belief, the Precursors had peacefully passed away after they fulfilled their mission in creating the Forerunners.<ref name="s203">'''Halo: Silentium''', ''page 203''</ref> The Forerunners believed the Precursors had shaped the Forerunners in their own image, and some even suggested that they may have done the same with humans.<ref>'''Halo: Cryptum''', ''page 26''</ref> By the time of the [[human-Forerunner wars]], [[Ancestors|ancient humans]] also claimed to be the sole inheritors of the Mantle, something contemporary Forerunners considered heretical.<ref>'''Halo: Cryptum''', ''page 112''</ref>

The majority of this information was mythology with a dubious historical basis, providing a set of explanations for the innumerable mysteries surrounding the Precursors. The facts were very different from what the Forerunners had ultimately chosen to believe.

According to the [[Librarian]], the concept of one-mind unity as seen in the [[Flood]] is not an aspect inherent to the Precursor race as a whole. There was corruption, but purity, division and unity, inclusion and exclusion and all Precursors were not the same. While the [[Primordial]] relished in suffering, others celebrated joy.<ref>'''[[Halo: Point of Light]]''', ''page 315''</ref> The fugitives on [[Netherop]] appeared to be of this kind of Precursor, choosing to hide themselves away but at the same time allowing the [[Defenders of the Sanctum]] to share their hiding place, kept them fed using the Precursors' technology and allowed them to live in some modicum of comfort for over thirty years which was an act of compassion that didn't match the Forerunner stories about the race.{{Ref/Reuse|Out17}} The Precursors also healed [[Rosa Fuertes]]' injuries and incurable prion disease on the condition that Rosa kept their existence a secret and warned her that everyone must leave as they would all die otherwise,{{Ref/Reuse|Out16}} likely aware that the Inner Sanctum would become uninhabitable once the power source was gone.{{Ref/Reuse|Out25}}

==History==
===Background===
{{Quote|The Gravemind no more understands the whole truth than we do. It is past all our understanding, from the greatest to the smallest.|[[Forthencho]]'s imprinted essence to the [[Librarian]]<ref>'''Halo: Silentium''', ''page 322''</ref>}}

The Precursors originated outside the [[Milky Way]] and arrived in the galaxy billions of years ago.<ref name="warfleet 8">''[[Halo: Warfleet]]'', p. 8</ref> They were an incredibly advanced race of beings who explored many galaxies and seeded them with life over the course of many billions of years as part of a grand experiment.{{Ref/Reuse|warfleet 8}} As transsentient beings, they existed on a level beyond that of conventionally [[Sentience|sapient]] biological organisms; they were described as "dreamers and makers whose minds transcended many realms and having infinite forms, many voices, and singular purpose".<ref name="warfleet 92">''Halo: Warfleet'', p. 92</ref> The Precursors were not tied to any particular physical form, assuming any shape as they saw fit; they would allow themselves to die away and be evolved anew over and over again, taking on numerous incarnations both physical and immaterial. They lived through different stages of technological and cultural development countless times, being at times hyper-advanced and spacefaring and at others living primitively and remaining confined to their worlds.<ref>'''Halo: Silentium''', ''page 321'' (''"The Precursors lived in many shapes, flesh and spirit, primitive and advanced, spacefaring and locked to their worlds ... Evolved over and over again, died away, were reborn, explored, and seeded many galaxies ..."'')</ref> The Precursors based their existence around the philosophical concepts of the [[Mantle]], [[Living Time]], and a meta-technological mechanism known as [[neural physics]], which enabled them to manipulate the fabric of the universe. According to the philosophical aspect of neural physics, the universe itself is a living entity, though vastly different in nature and scale from organic beings.<ref name="c103">'''Halo: Cryptum''', ''page 103''</ref> The Precursors' stewardship for all life involved the belief that all experience of biological organisms enriched the greater, universal whole,<ref name="sweetness">'''Halo: Primordium''', ''pages 365, 367''</ref> something they experienced firsthand through the constantly changing nature of their own existence. To contain their vast knowledge and experience the Precursors created the [[Domain]], a transcendent quantum reservoir of information later accessed by the Forerunners.<ref name="sil320">'''Halo: Silentium''', ''pages 320-323''</ref> The Precursors were not strictly benevolent, considering strife, pain and indeed evil an inherent part of the universe. The struggles of good and evil, the pleasures and pains of life, added to the 'sweetness', a sensation or emotional state that seemed to not have a human-analogue. 

The Precursors were responsible for seeding the Milky Way with life, creating the galaxy's diverse composition of species to become "new tools and companions", and engineered millions of star systems. Over time, they would also judge whether a species was worthy of the Mantle, their assumed role of guardianship of all life. The humanoid species native to the world of [[Ghibalb]], who would come to be known as the [[Forerunner]]s, were next chosen for this task. Originally created by the Precursors to serve as their assistants and adjutants,{{Ref/Reuse|warfleet 8}} the Forerunners were eventually judged to be unworthy of taking on the Mantle and according to one record, planned to be wiped out<ref>'''Halo Mythos''', ''page 7''</ref>, and the Precursors instead decided that the responsibility would fall on the shoulders of another of their creations; a collection of species referred to as [[human]]ity, hailing from the planet known as [[Earth|Erde-Tyrene]]. According to this record, the Forerunners' made an expedition to Path Kethona, where they encountered their creators, and accidentally found out this genocidal plan <ref>'''Halo Mythos''', ''page 7''</ref> around [[10,000,000 BCE]]. The Forerunners decided to prevent this fate and [[Forerunner-Precursor war|furiously retaliated against]] their creators and drove them to near-extinction, first in the Milky Way and eventually in the satellite galaxy of [[Path Kethona]]; only a small number managed to escape the Forerunners' campaign of extermination. According to another record, the Precursors decision to pass the Mantle to humanity seeded antipathy in the hearts of the Forerunners and this combined with some Forerunners coming to believe the Precursors were planning to exterminate them, caused them to commit genocide against their creators in a one-sided war.{{Ref/Book|Id=Enc22P312|Enc22|Page=312}} This account was corroborated by the Gravemind, whom contained the consciousness of the Primordial, a Precursor and other Precursor essences who told the Ur-Didact that the Forerunners struck against their creators unprovoked.<ref>'''Halo: Silentium''', ''page 209''</ref>

During this war, some Precursors settled on [[Netherop]] with the Tier 6 civilization that was already on the planet. These Precursor fugitives used a weapon later called the [[Divine Hand]] to destroy a [[Guardian Custode]] that was sent after them by the Forerunners. However, the effects of their weapon devastated Netherop, turning a once lush planet into a barely inhabitable wasteland. The indigenous population was wiped out, but the Precursor fugitives remained in hiding on Netherop for over a hundred thousand years.{{Ref/Novel|Id=Out|Out}}

===Return===
{{Main|Flood}}
{{Quote|We are the Flood. There is no difference. Until all space and time are rolled up and life is crushed in the folds... no end to grief, war or pain. In a hundred and one thousand centuries... unity again, and wisdom. Until then - sweetness.|The [[Primordial]] speaking to the [[IsoDidact]]}}

A few Precursors escaped or were spared by the Forerunners. They either went into suspended animation or became molecular dust that was meant to eventually regenerate into their past forms. However, over millions of years, the dust became defective, failing to reconstitute the Precursors and instead inducing madness and mutations in lifeforms that came in contact with it. This form would later be known as the [[Flood]]. Far from accepting failure and extinction, the Precursors viewed the Flood as a means to bring unity to the galaxy as well as punish the Forerunners for their insolence. Vowing that none of their creations would rise against them again, the Precursors decided that all life would be deprived of free will and merged into one; in the end, the sum of the Precursors' creation would be a reflection of themselves and the suffering their creations caused them.<ref>'''Halo: Silentium''', ''String 13''</ref>

However, not all Precursors chose this course of action. After the genocide, those Forerunners who refused to partake in the genocide of their creators were exiled to a planet in Path Kethona. While there they discovered two Precursor survivors who were not corrupted like the [[Primordial]] but were instead of a gentler and kinder nature. The Forerunners tried to save them but the survivors chose to die with the rest of their species.{{Ref/Reuse|POL}}

[[File:Mythos Primordial.JPG|250px|thumb|left|The Primordial and Mendicant Bias.]]
Around [[107,445 BCE]], ten million years after the Forerunners' genocide of the Precursors, [[Ancestors|humanity's interstellar empire]] came into contact with the Precursor powder which would, over several centuries, bring forth the Flood. The Flood initially ravaged humanity's colonies until receding from the galaxy on its own accord, awaiting for a better moment to exact their final vengeance on the Forerunners. The Flood intentionally allowed some humans to go uninfected, leaving the implication of a possible cure that would misdirect efforts in its next assault, while the truth of the humans' genetic attack on the Flood was lost until it was far too late. Around the same time, a human exploratory group led by [[Yprin Yprikushma]] discovered a small planetoid at the edge of the Milky Way. Hidden within it was a large [[stasis capsule]] containing an ancient being whom they later named the [[Primordial]]—in fact the last intact Precursor, mutated to survive the passage of eons.<ref>'''[[Halo Mythos]]''', ''page 9''</ref> They transported the capsule and its captive to the human capital world of [[Charum Hakkor]] and found a way to communicate with the being, which claimed to be the last Precursor.

When human scientists questioned the imprisoned being as to the nature of the Flood, the Primordial's response horrified the humans so deeply that many of them committed suicide.<ref>'''Halo: Cryptum''', ''page 271''</ref> Because the Forerunners did not then know about the relation between the Flood and the Precursors' own remains, they instead mistook the humans' destruction of planets as an act of war, instead of attempting to cleanse the Flood, leading to the [[Human-Forerunner war]]. Around ten thousand years later, the [[IsoDidact]] interrogated the Primordial on [[Installation 07]], receiving only vague responses as to the fate of the Precursors and their relationship with the Flood. Enraged, the IsoDidact then executed the being. The Primordial faced its end with calm satisfaction, stating that the Forerunners' defiance and, indeed, its own death through the artificial passing of a billion years within an [[Slipspace bubble|accelerating chronological field]], would only add up to the total "sweetness" of life's struggles while asserting its confidence that all life would still succumb to the Flood in the end.<ref>'''Halo: Primordium''', ''page 362-366''</ref>{{Ref/Reuse|sweetness}} The [[Ur-Didact]] later discovered that the [[Gravemind]] retained the thoughts and memories of the Primordial;<ref>'''Halo: Silentium''', ''page 167''</ref> before its demise, the being had transferred its consciousness into the Flood's compound mind.<ref>'''Halo Mythos''', ''page 32''</ref> However, not even the Gravemind could fully access or comprehend the wisdom the Precursors once had, flawed and fallen as it was.<ref>'''Halo: Silentium''', ''page 322''</ref>

In the final hours of the Forerunners' war with the Flood the Gravemind sent a group of imprinted humans, including [[Forthencho]], Lord of Admirals, to deliver a message to the [[Librarian]], who was stranded on Erde-Tyrene. Forthencho revealed to her the truth about the Precursors and that the Domain was, in fact, the mythical [[Organon]], which would be destroyed by the [[Halo Array]]'s immediate firing. By withholding this information until the very end, when the Halos' activation could no longer be stopped, the Precursors ensured that the Forerunners would unwittingly destroy all records of their history and their cultural heritage, or "kill their own soul" as phrased by the Librarian.{{Ref/Reuse|sil320}} This was the culmination of the Precursors' insidious plan of vengeance against the Forerunners, set in motion ten thousand years earlier with the revelation of the Flood. While the firing of the Halos seemingly quelled the Flood, the Precursors (through the Gravemind) had already accomplished what they intended: to punish the Forerunners for their defiance not only directly via the Flood, but also allowing the Forerunners' own scheming and internecine feuding to gradually tear down the Forerunners' deepest-held precepts and beliefs. By the time of the Halos' firing, in addition to the near-extinction of the Forerunner species, the Forerunners were forced to admit their many failures and give up the Mantle, ensuring that they would not rise again despite their Pyrrhic victory.<ref>'''Halo: Silentium''', ''pages 323-324''</ref>

===Rebirth===
During the genocide of the species in [[Path Kethona]], two Precursors had found shelter and were discovered by the exiled Forerunners who hid them and tried to heal them. However, the Precursors were beyond the Forerunners' ability to save and although the Precursors possessed the ability to heal themselves, they chose to let nature take its course. After dying, the two Precursors became samples that were studied and encoded, and planted in the ground as seeds that would germinate for a million years. Their sprouts that climbed to the surface took even longer and bloomed only in the last million years. Unlike the [[Primordial]], these were Precursors that celebrated joy instead of relishing in suffering and as a result, the blooms were not left corrupted with violence and misery but instead were clean, beautiful, and bright.

Driven by her own ''[[geas]]'' from the Precursors to fix the path and set right what the Forerunners did wrong, the [[Librarian]] located the specimens while in Path Kethona searching out the origins of the [[Flood]]. Returning home with the specimens, the Librarian kept her discovery out of her report to the Ecumene Council and enlisted the help of the crew of the ''[[Audacity]]'' to transform a small [[shield world]] in its construction phase, [[Bastion]], and make it what it needed to be to nurture this eventual new species. The Librarian had the starship ''[[Eden (spaceship)|Eden]]'' built to carry the Precursor seeds and blooms to a world outside of the Milky Way galaxy that is ideal for planting and growth and where they can't be reached by the Flood. There, in some distant future, life on the planet will emerge and grow sentient, following the complete genetic code of the Precursors and rebirthing the race. However, they will be utterly free of genetic memory and will be able to build a new civilization with a clean slate.

In [[2558]], Bastion is rediscovered by [[Rion Forge]] and [[343 Guilty Spark]]. With their help, [[Keeper-of-Tools]] launches ''Eden'' to begin the mission to rebirth the Precursor race.{{Ref/Novel|Id=POL|POL}}

===Netherop===
In late [[2559]], forces from the [[UNSC]], the [[Swords of Sanghelios]] and the [[Banished]] sought the [[Divine Hand]], the weapon that the Precursor fugitives had used on [[Netherop]] to destroy an attacking [[Guardian Custode]]. The hope was to use this mysterious weapon to defeat [[Cortana]] and the [[Created]].{{Ref/Reuse|Out}} After encountering examples of technology that didn't match the Tier 6 inhabitants of Netherop, [[Olympia Vale]] and [[Keely Iyuska]], remembering the [[Gravemind]]'s story of the [[Forerunner-Precursor war]], realized that the fugitives were Precursors and worried that they might have survived the eons. However, these Precursors appeared to be compassionate rather than vengeful like the [[Primordial]] was because, as noted by Iyuska, they allowed the [[Defenders of the Sanctum]] to share their hiding place, kept them fed, and allowed them to live in some modicum of comfort for over thirty years using the Precursors' [[nanotechnology]].{{Ref/Novel|Id=Out17|Out|17}}

At the same time, two Precursors approached a severely injured [[Rosa Fuertes]] with the choice of whether to exist or not. The Precursors made it clear that she must not tell anyone of their encounter and healed Rosa of her incurable prion disease. The Precursors told Rosa that the species called itself the Veiled Ones, then the Lost Ones and now Nothing and warned her that everyone must leave the planet with her or they would die.{{Ref/Novel|Id=Out16|Out|16}} Rosa subsequently kept quiet about her encounter with the Precursors, sure that they were still with her, not wanting to know what they would do if Rosa betrayed them, and knowing that, real or not, they had saved her life.{{Ref/Novel|Out|22}}

Subsequently, the Banished were allowed to take the Precursor weapon before all of the survivors of the battle fled Netherop before [[Created]] forces could arrive to investigate.{{Ref/Novel|Out|24}} Without the power source for the Divine Hand, the [[Sanctum of the Ancients]] and the remaining Precursor technology on the planet lost power, causing the food and water that had been grown for the Defenders of the Sanctum to become withered and contaminated, leaving [[Nizat 'Kvarosee]] and [[Tam 'Lakosee]] facing imminent death after they were left behind, fulfilling the Precursors' warning to Rosa that anyone who remained behind would die.{{Ref/Reuse|Out25}}

==Appearance==
Due to the Precursors' transsentient nature, their true physical form (if they took one) is unknown. According to the Gravemind, they could assume any physical or immaterial form they saw fit, having done so over billions of years of existence.<ref>'''Halo: Silentium''', ''page 321''</ref>

At least three forms are known with some degree of detail. One form of Precursor, or at least an infantile stage of them, took the form of green teardrop plants as large as melons that when exposed to light would unfurl wide leathery leaves that would fan gently with the grace of a bowing dancer, and expose a glowing starburst of delicate white blooms dangling from groups of lantern-like stems.{{Ref/Novel|PoL|page 263}}

Another form of Precursor is the Primordial who was massive in size; the mold encapsulating the being on Charum Hakkor outlined a being approximately fifteen meters tall and eleven meters wide with the Ur-Didact seeing it on Charum Hakkor describing it as possessing an insectoid head, four arms, and two degenerate legs and a long, segmented "tail" being attached to the base of the skull and tipped with a two meter-long barb. Each of its hands had three fingers and a central opposable thumb. The face of the Primordial had been likened to that of a eurypterid, or "sea scorpion," a creature that the Precursors had allegedly seeded on a number of planets including Earth. Its head was flattened, with oval compound eyes and insect-like mouthparts.<ref name="c277">'''Halo: Cryptum''', ''page 277''</ref><ref>'''Halo: Cryptum''', ''page 119''</ref> Later, aboard Installation 07, the being was described as having a large number of legs which it held in a curled-up position similar to a spider. The creature's torso was described as "grossly fat," and its skin was covered in a glassy, crystalline coating; a fine powder often fell from its body, perhaps Flood spores or the same powder responsible for the original Flood outbreak. As a Gravemind, the Primordial was capable of shifting its physical form to an extent, such as rearranging its limbs.<ref name="p108">'''Halo: Primordium''', ''page 108-109''</ref> However given that the Primordial was said to be heavily mutated to survive vast spans of time, it is likely it no longer resembled other Precursors as they appeared during the time of the Forerunner-Precursor war thus it is likely this form was unique to the Primordial.<ref name="mythos 9">'''[[Halo Mythos]]''', ''page 9''</ref>

The most detailed and most prominent form of the Precursors known to the inhabitants of the Milky Way is their form as the Flood, a species of highly virulent parasitic organisms that reproduce and grow by consuming sentient lifeforms of sufficient biomass and cognitive capability. This form was initially born of corrupted Precursor remains.<ref>'''Halo: Silentium''', ''pages 181-182''</ref>

On [[Netherop]] the Precursor fugitives, of which there appeared to be at least two, took on the form of the pearl ambiance around [[Rosa Fuertes]].{{Ref/Reuse|Out16}}

==Technology==
{{Quote|The Flood changes everything. Not just flesh. Space itself is infected. That's the power the Precursors once had...  isn't it? They shaped and moved galaxies! They created us! How did we ever manage to defeat them?|The [[Ur-Didact]] to the [[IsoDidact]]<ref name="s223">'''Halo: Silentium''', ''pages 223-224''</ref>}}

Precursor technology was incomprehensibly advanced, to the point that the Forerunners labeled it [[Technological Achievement Tiers|Tier 0]], or "Transsentient". Precursors based their technology upon what Forerunners called [[neural physics]]: the concept that inanimate matter and thought are inextricably linked and that the universe itself is effectively a living entity.{{Ref/Reuse|c103}} By drawing from the fundamental energies of the universe,<ref name="s40">'''Halo: Silentium''', ''page 40'' (''"These gray, eternal whorls stretched to middle orbit, where their rotating bands drew constantly and silently from the neurophysical energy of raw space in ways we still do not understand."'')</ref> the Precursors built exotic, virtually indestructible architecture and traveled across interstellar distances using a superluminal transit mechanism based upon the same principle.<ref name="s213">'''Halo: Silentium''', ''page 213''</ref> It was believed by Forerunners that the Precursors also used neural physics techniques to construct artificial planets and star systems, with Charum Hakkor believed to be one such planet.<ref>'''Halo Mythos''', ''page 15''</ref> The Precursors traveled between worlds in vessels that used incredibly advanced [[artificial intelligence]] constructs known as [[knowledge engine]]s and walked upon [[star road]]s.{{Ref/Reuse|warfleet 8}} The Precursors created [[Stasis capsule|stasis capsules]] to contain beings within stasis.<ref>'''Halo: Cryptum''', ''page 130''</ref> The [[Halo Array]], being neurological weapons, are one of the only ways to destroy or otherwise damage Precursor artifacts. This was first evidenced when [[Charum Hakkor]] was used as a testbed for [[Installation 07|one of the Halos]]: the weapon's firing shattered every Precursor artifact on the planet. This also explains the lack of any Precursor ruins in modern society, as most, if not all, were destroyed when the Halo Array fired and sterilized the galaxy at the end of the [[Forerunner-Flood war]].<ref>'''Halo: Silentium''', ''page 326''</ref>

Some Precursor artifacts were known to precede the Forerunners by hundreds of millions or even billions of years and, being impervious to conventional forms of damage, were durable enough to survive being cycled inside planets' crusts by plate tectonics.<ref>'''Halo: Cryptum''', ''page 39''</ref> Precursor artifacts were often encountered by [[Miner]]s, who obtained and recorded them but rarely held any particular interest in them. The most coveted Precursor artifact among the Forerunners was known as the Organon, which was allegedly capable of activating all other Precursor artifacts.<ref>'''Halo: Cryptum''', ''page 19''</ref> In truth, the Organon was a Precursor knowledge engine known as [[Abaddon]], who served as the overseer and guardian of the [[Domain]]. Although incorporeal, Abaddon was capable of interacting with the physical world in various ways, even vaporizing corporeal beings at will.<ref name="ptk">'''[[Halo: Fractures]]''', "[[Promises to Keep]]"</ref>

The Precursors also left behind a small number of mysterious deep-space artifacts known as "anchors" — large, anomalous masses which released no radiation. They were generally regarded as unstable and dangerous; the Forerunners had recorded strange phenomena near the masses, including ships vanishing and surviving crews suffering severe mental trauma, requiring extensive proto-geometric therapy to restore their minds' neural topology to its normal state.<ref>'''Halo: Silentium''', ''pages 69-70''</ref> Precursor construction was gray-silver in color, much like that favored by the Forerunners. When witnessed in a collapsed state on Charum Hakkor, the construction material had shattered along crystalline planes.<ref>'''Halo: Cryptum''', ''page 117''</ref> The Precursors also built cyclopean laboratories described as being made of "crystallized reality".{{Ref/Reuse|warfleet 8}}

Among the most impressive of the Precursors' structures were the enormous [[orbital arch]]es and [[star road]]s, unbending filaments woven into the fabric of reality which were used to connect entire worlds and star systems.<ref>'''Halo: Cryptum''', ''page 102''</ref><ref>'''Halo: Cryptum''', ''page 118''</ref> These structures were once plentiful in the galaxy, forming graceful curves across many star systems. They appeared to be mostly dormant and unchanging, apart from automatic adjustments based on changes in planetary orbits.<ref>'''Halo: Silentium''', ''page 114''</ref> Other types of Precursor constructs included structures referred to as planetary fortresses and citadels.<ref name="s187">'''Halo: Silentium''', ''page 187''</ref> Toward the end of the Forerunner-Flood war the Flood began to reactivate and employ these formerly inert Precursor artifacts against the Forerunners, being able to control them due to its Precursor origins.{{Ref/Reuse|s187}} These artifacts (mainly star roads) were what eventually turned the war in the Flood's favor as they were capable of effortlessly either outright physically tearing apart Forerunner fleets or remotely deactivating their weapons, [[ancilla]]s, and shields, rendering them helpless against the Flood.<ref>'''Halo: Silentium''', ''pages 199-189, 214-215''</ref>

The Precursors' rekindled might extended beyond the mastery of technological artifacts. After reaching the [[Key Mind]] stage, Flood compound minds gained the ability to tap into neural physics and along with it the Precursors' reality-mutation capabilities.<ref>'''Halo: Silentium''', ''pages 186-187''</ref> When moving across the galaxy, Flood-controlled Precursor constructs would convert space-time itself to be unsuitable for Forerunner [[slipspace drive]]s due to the differences between the [[slipspace]] travel used by the Forerunners and the Precursors' neural physics-based transit. Ships using this form of superluminal travel would momentarily radiate multiversal residues accrued during the journey upon return to normal space.{{Ref/Reuse|s213}} The Forerunners suspected that the Precursors possessed unknown means of correcting causality other than the [[reconciliation]] Forerunner ships were subject to.<ref>'''Halo: Silentium''', ''page 111''</ref> The widespread use of neural physics transit affected the galactic-scale magnetic fields that marked the borders of the [[ecumene]]'s [[thema]]s. The effects of the Precursors' manipulation of space could even be felt by individual beings; toward the end of the Forerunner-Flood war Forerunners began to perceive starlight as possessing a hostile, repelling quality.{{Ref/Reuse|s223}}<ref>'''Halo: Silentium''', ''page 325''</ref>

The Precursors were able to create and place Geas on other species as demonstrated by how they placed one on the ancestors of the Librarian which led her to find Precursor seeds in Path Kethona and later set about ensuring the rebirth of uncorrupted Precursors in another galaxy eons later.{{Ref/Novel|PoL|page 265}}

The Precursors held a knowledge of slipstream space technologies beyond even the Forerunners' as demonstrated by them having created at least one slipspace core, a large, quantum-engineered crystal which was found and later used by the Forerunners to create slipspace drives for their ships with the exotic composition and slipspace interactions of said core being incomprehensible to the Forerunners, and never replicated by them.{{Ref/Book|Id=Enc22P319|Enc22|Page=319}} 

Perhaps the Precursors' most extraordinary creation was what the Forerunners knew as the [[Domain]]: a vast reserve containing the totality of the Precursors' accumulated knowledge and experience - amounting to a hundred billion years, with most of the information gathered originating from the beginning of the universe if not earlier. This reserve of knowledge was contained in Precursor constructs in the Milky Way galaxy and projected a massive field through which the records could be accessed anywhere regardless of locality. The Domain itself was also a conscious entity, although this only became apparent to most Forerunners near the end of the Forerunner-Flood war. The Domain would later be discovered and appropriated by the Forerunners as a store of their own records and knowledge, becoming a principal element of their culture. Despite this, the Domain remained highly esoteric to the Forerunners; not even its origin and true nature were known. With the activation of the Halo Array and the galaxy-wide unraveling of Precursor neural physics, the Domain and all knowledge contained therein was lost along with all Precursor architecture.{{Ref/Reuse|sil320}} While a group of surviving Forerunners later managed to reactivate the Domain, it remains unclear how much of the knowledge it once contained has been successfully recovered.{{Ref/Reuse|ptk}}

However, not all Precursor technology was based on neural physics. A group of Precursor fugitives on [[Netherop]] instead used an extraordinarily advanced form of self-directing [[nanotechnology]] to build [[Sanctum of the Ancients|their base]] and [[Divine Hand|their weapon]].{{Ref/Reuse|Out17}} [[Keely Iyuska]] suggested that such technology was probably just a parlor trick to a species as advanced as the Precursors.{{Ref/Novel|Out|13}} The Precursor nanotechnology was unaffected by the firing of the Halo Array and was still active a hundred thousand years later where it was made use of by the [[Defenders of the Sanctum]], a group of [[Sangheili]] exiles on the planet.{{Ref/Reuse|Out}} The technology was powered by a [[vacuum energy condenser]] and once it was removed,{{Ref/Novel|Out|21}} all of the Precursor technology shut down, causing the food and water that it had grown for the Sangheili to wither and become contaminated.{{Ref/Novel|Id=Out25|Out|25}}

==Production notes==
*Precursors are [[wikipedia:Lovecraftian horror|Lovecraftian]] inspired entities as Greg Bear mentioned in a reply on his blog.<ref>[https://www.gregbear.com/archives/board_2015.htm GregBear.com:Board 2015:Precursors] "If there are any precursors to the Precursors, they're probably E.E. Smith's Eddorians in his Lensmen series, and the wonderfully weird psychic monsters unearthed from the deeps in John Brunner's THE ATLANTIC ABOMINATION. Those, plus a starshipload of Lovecraft's Cthulhu and other pulp denizens!"</ref> When writing for the Precursors he took inspiration from the Eddorians in E.E. Smith's Lensmen series, the psychic creatures in John Brunner's THE ATLANTIC ABOMINATION novel and [[wikipedia:Cthulhu|Cthulhu]] (notably the tentacle draped mouths) and other deities in H. P. Lovecraft's Cthulhu Mythos.
*Precursors have been described as [[wikipedia:Cthulhu Mythos deities|godlike]] by Greg Bear in replies on his blog.<ref>[https://www.gregbear.com/archives/board_2011_2.htm GregBear.com:Board 2011:The wonderful mysteries of the Forerunner Trilogy.]</ref> Additionally, the Latin root word "trans" means "across" or "beyond."  "Sentience" is the ability to experience sensation, and is often used to imply sapience, the ability to think. A transsentient being may thus be considered beyond any recognized being and be on the level of godhood.
==Trivia==
*The term ''precursor'' means "one that precedes and indicates the approach of another". This is also the definition of the term ''forerunner''. 
*The Precursors (and by extension the Flood) fill a similar narrative role to the [[marathongame:W'rkncacnter|W'rkcacnter]] from [[Bungie]]'s ''[[Marathon]]'' trilogy. Godlike cosmic beings, the W'rkcacnter long held sway over the universe before being imprisoned by the [[marathongame:Jjaro|Jjaro]], the spiritual predecessors to the Forerunners. They (like the Flood) are accidentally unleashed in the setting's present day when the alien collective known as the [[marathongame:Pfhor|Pfhor]] (a major inspiration for the [[Covenant]]) recklessly use a Jjaro superweapon against humanity. It is ambiguous whether the W'rkncacnter are a single entity or an entire race with a collective consciousness while the Precursors did not share a collective consciousness originally according to the research done by the Librarian.

==Gallery==
<gallery>
File:GregBearPrecursor.jpg|A preliminary sketch of the Primordial drawn by [[Greg Bear]].
</gallery>

==List of appearances== 
*''[[Halo 3]]''
**''[[Bestiarum]]'' {{Fm}}
**''[[Terminal (Halo 3)|Terminals]]'' 
*''[[Halo: Cryptum]]'' {{1st}}
*''[[Halo: Primordium]]''
*''[[Halo: The Thursday War]]'' {{Mo}}
*''[[Halo: Silentium]]''
*''[[Halo: Hunters in the Dark]]'' {{Im}}
*''[[Halo 5: Guardians]]'' {{Im}}
*''[[Halo Mythos]]''
*''[[Halo: Renegades]]'' {{Mo}}
*''[[Halo: Point of Light]]''
*''[[Halo: Outcasts]]''
*''[[Halo: Epitaph]]''

==Sources==
{{Ref/Sources|2}}

{{Navbox/Species}}
{{Organizations}}

[[Category:Precursor| ]]
[[Category:Sapient species]]